This invention relates to electrical power generation, more particularly to a novel hybrid power generating system to be known as the Geothermal Wind System (GWS), where a tunnel and shaft provide a circulating wind system to power turbines which generate electricity or by transferred mechanical energy turn electrical generators, using a passive geothermal heat exchange to create gravity induced buoyancy of air. There are two modes based on the same principle from which many embodiments of GWS can be created: The Low Temperature Mode harnesses geothermal temperature that is approximately the same as the yearly average of the outside temperature allowing bi-directional winds to flow upward or downward depending on the outside temperature. The High Temperature Mode is used where the geothermal temperature is greater than 49 C degrees or higher than the highest external temperature. This mode of high geothermal temperature always generates wind upward. In both of these modes the tunnel and the shaft act as a natural heat exchanger and allow the circulation of wind which propels one or more turbines connected to electrical generators.
An advantage of the wind tunnel herein depicted, is that a venturi restriction can be designed to focus the wind into a turbine. The present art teaches a novel Adjustable Radial Wind Venturi which allows the tunnel to constrict from all sides using six or more petals imposing the least wind resistance to focus higher or lower wind speeds onto the turbine for maximum performance.
Since buoyancy and gravity create the driving force, the greater the elevation difference between the two portals of the tunnel and shaft, the more powerful the winds and greater the electrical power generated. In areas where there is low elevation and low geothermal heat, the shaft can be extended as a stack with the spoil talus compacted as a mound around the stack for insulation.